This invention relates generally to an adhesive composition and, more specifically, to a UV-curable adhesive composition useful for fabricating an optical disc. The present invention also pertains to a method of preparing an optical disc using the above adhesive composition and to an optical disc produced thereby.
Various optical discs such as of a read-only (RO) type, a write-once (WO) type or a rewritable (RW) type are known. These optical discs have a transparent substrate on which an optical information recording layer is formed by, for example, sputtering or vacuum deposition of a metal or metal oxide. Recently, optical discs, such as digital video discs (DVD), having two or more recording layers were proposed. Such a multi-recording-layer optical disc is generally prepared by bonding two optical discs, each having a transparent substrate and one or more optical information recording layers, together.
One known UV-curable adhesive composition for bonding optical discs contains a polymerizable unsaturated compound, such as (meth)acrylate, and a polymerization initiator. When the optical discs to be bonded have a metal, alloy or metal oxide layer as the reflective layer, however, the known adhesive composition fails to have a satisfactory bonding strength.